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<b>let </b><font color="Maroon">a</font> be  <a href="ordinal1.html#V7">natural</a>  <a href="ordinal1.html#NM1" target="_self">number</a> , <font color="Maroon">b</font> be  <a href="ordinal1.html#V7">natural</a>  <a href="ordinal1.html#NM1" target="_self">number</a> ;<br/>

<b>assume </b><a NAME="E1:5"/>
( <font color="Maroon">a</font> <a href="xxreal_0.html#R1">&lt;</a> <font color="Maroon">b</font> &amp; 1 <a href="xxreal_0.html#R1">&lt;</a> <font color="Maroon">b</font> )
 ;<br/>

<b>hence </b><a NAME="E2:5"/>
<font color="Maroon">a</font> <a href="binarith.html#K3">-'</a> 1 <a href="xxreal_0.html#R1">&lt;</a> <font color="Maroon">b</font> <a href="binarith.html#K3">-'</a> 1
 <b>by </b><i><a class="ref" href="sprect_3.html#T10">SPRECT_3:10</a></i>;<br/>


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